The drug codeine
is metabolized mostly in liver
, and its concentration in urine depends upon person to person, the condition of liver, if patient is alcoholic or not any many more factors, but mostly it gets excreted in 48 to 72 hours if everything is normal.
I just advise you to make him take plenty of liquids, fluids ,which will flush out the metabolites more fast.
hope my answers are helpful to you.
Dr Hari Om Chandrakar